The present invention relates to an improvement in a rotary sliding closure unit and specifically to an arrangement for preventing air from reaching abutting sliding surfaces of refractory members of such unit.
More specifically, the present invention relates to such improvement in a rotary sliding closure unit for controlling the discharge of molten metal from a metallurgical vessel, the unit being of the type including a stationary refractory member having a discharge opening, fixed mounting means for supporting the stationary refractory member at a position with the discharge opening thereof in alignment with an outlet of the metallurgical vessel, a rotary refractory member having a discharge opening, and rotary mounting means for supporting the rotary refractory member in abutment with the stationary refractory member along respective complementary abutting sliding surfaces and for rotating the rotary refractory member with respect to the stationary refractory member between an open position whereat the discharge openings are in alignment and a closed position whereat the discharge openings are out of alignment. This general type of rotary sliding gate or rotary sliding closure unit is disclosed in European patent specification No. 00 40692.
In this type of unit, the refractory closing components or members slide relative to each other under an initial stress and are subjected to considerable wear due to the rotation of the rotary refractory member at elevated temperatures while being acted upon by the molten metal. A number of attempts have been made in the past to reduce the amount of wear of the refractory members to thereby increase the service life of the closure unit. For example, attempts have been made to employ selected combinations of materials of the refractory members which slide relative to each other. However, such attempts have lead to an additional problem, namely a reduction in resistance to oxidation and a decrease in sliding properties of the refractory members.